misseva,
The serial number for the sewing machine is located under the bed on the front of the machine and those in the know can estimate a date of manufacture which is probably late Teens or Twenties. The $175 seems about right if complete with foot controller, attachments, and the insert that appears to be missing from the bed. Also worth considering is condition of electrical components and whether your able to work on them if you plan on sewing with this gem. I tend to expect the worst with 90-100 year old electrical and figure on rewiring as the best case scenario.
Jon